As computer systems become more complicated and more powerful, and as power becomes more expensive to provide, it has become desirable in the computer industry to manage the power that the computer systems are using. For example, a server system or a raised floor data center can require large amounts of power to run and cool, even when the system is not fully utilized.
As a result, power management systems (e.g., a system utilizing power management events (PMEs) or power specifications) have been developed to allow computer systems to use power more efficiently. More specifically, power management systems allow the computer system to power up or power down depending on their usage. Such a computer system that utilizes a power management scheme uses less power to run and maintain because the system powers down when not in use.
Although power management events (PMEs) are beneficial for reducing power consumption of a computer system, PMEs can sometimes interfere with other features of the computer system. For example, many peripheral components are hot swappable. That is, a peripheral component (e.g., a PCI card) can be added or removed from the computer system without powering the computer system down. In so doing, the operating system of the computer system can be available to process requests from various sources at the same time the computer system is being repaired or upgraded.
To provide hot swappable capabilities in a computer system, the peripheral component interface (e.g., PCI slot) wherein the hot swap is occurring, must be powered down to avoid damage to the components being installed or removed from the peripheral component interface. If the peripheral component interface (e.g., PCI card slot) is not completely powered down, the peripheral component or the entire computer system could be damaged while upgrading or repairing the computer system. Special circuitry is typically used to power down a particular peripheral component interface when the peripheral component is not fully installed. Once the peripheral component is fully installed, the peripheral component interface is powered up and the newly installed peripheral component can be used. As a result of powering down the peripheral component interface, the computer system sees the peripheral component interface as asserted.
If the computer system is powered up and working, seeing an asserted peripheral component interface does not cause problems. However, if the computer system is turned off, there is a risk during the installation of a peripheral component that the computer system will determine that the peripheral component interconnect is asserted and will power up the computer system. If the computer system is powered up in the process of swapping a peripheral component, there is a risk of injuring the person swapping the peripheral component, and/or damaging the peripheral component or the entire computer system. For example, if the peripheral component is not fully installed in the peripheral component interface, and the computer system powers up from a false assertion, there is a risk of a short circuit.
Thus, there exists a need for a system and method for preventing false assertions associated with a peripheral component interface.